A four-month-long investigation involving an undercover cop posing as a student has led to the arrest of ten Angleton High School students on drug charges, the Houston Chronicle reports.

According to the report, five of the arrested students are adults and five are juveniles. Authorities told the paper the 28 charges against them related to the selling of drugs.

Lieutenant Chris Reioux told the paper the investigation began when the school district reached out to authorities.

"Basically the school district reached out to us," he told the Houston Chronicle. "We provided the undercover officer and funded the operation and they took care of getting the officer enrolled in the school."

Investigators told KTRK TV students sold prescription drugs like Oxycodone, Ritalin, and Hydrocodone, as well as marijuana.

The station reports that the school's motivation to seek help was a recent student survey about alcohol and drug prevalence.

"Nothing we've done has made a significant difference and if you keep doing the same thing and nothing changes, there is something wrong with you," Angleton ISD Superintendent Patricia Montgomery told KTRK.

Police told KHOU that a lot of the drugs sold at the school came from home medicine cabinets, and that the undercover agent has since left the school.